Appendix D Food Codes for NHANES - OEHHA

Scientific Review PanelSRP Draft Version 2 February,June 2012
contribution to blood lead was significantly greater (p< 0.001) during the post
pregnancy period than during the 2 nd and 3 rd trimesters.
The contribution of skeletal lead to blood lead during the post-pregnancy period
remained constant at the increased level even though the duration of breastfeeding
varied from 1 week to 6 months. The authors concluded that the
increased contribution of skeletal lead both during pregnancy and in the post
pregnancy period is consistent with increased bone resorption and may be
associated with inadequate calcium intake.
Sowers et al (2000) followed lactating women enrolled in prenatal program
located in Camden, New Jersey between 1997 and 2000 (Sowers et al., 2002).
These women were part of a larger cohort of 962 women enrolled in study of
calcium metabolism in pregnancy and lactation. A nested cohort of 15 women
with a mean (standard deviation) age of 23.7 (5.42) years, who provided breast
milk samples through 6 months postpartum or longer and were unaware of their
blood lead levels, was included in the study. Blood and milk lead levels along
with measures of bone loss and osteocalcin concentrations were evaluated.
Authors reported the precautions taken to avoid contamination of milk samples
by environmental lead.
The arithmetic mean (standard deviation) (µg/dL) of blood lead levels at delivery
for 15 breast-feeding and 30 randomly selected bottle-feeding women were 1.37
(0.78) and 1.31 (1.10) respectively. Mean maternal blood lead levels rose to 1.6,
(1.7) µg/dL at three and six months during lactation, respectively. Compared to
bottle-feeding women, blood lead levels from breast-feeding women were
consistently higher by 15 – 35% during the first six months postpartum. Authors
found that breast-feeding women had greater bone loss as reflected in the bone
change data and higher serum osteocalcin concentrations than bottle-feeding
women.
The arithmetic mean of lead in breast milk samples (standard deviation) were 5.6
(4.2) and 5.9 (3.87) µg/L at three and six months post partum. Breast milk lead
was also measured 1.5 and 12 months post partum. However, authors did not
measure blood lead at 1.5 months, did not indicate how many women were still
breast-feeding and did not attempt to estimate how many liters/day study
subjects produced. The relative increase in blood lead levels from delivery to an
active lactating period (e.g. one to 6 months) is consistent with the relative
increases in blood lead found in other studies (see Table J.4-3).
Tellez-Rojo et al (2002) concluded that maternal bone lead levels are an
important predictor of maternal blood lead levels over the course of lactation. In
fact, bone lead from past exposures can contribute an additional 40% of the lead
measured in blood during lactation (see Table J.4-3) (Tellez-Rojo et al., 2002).
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